Study of tritium recovery from lithium titanate pebbles with neutron irradiation

Ochiai, Kentaro; Edao, Yuki; Kawamura, Yoshinori; Hoshino, Tsuyoshi; Ota, Masayuki; Konno, Chikara  

In order to investigate the tritium recovery property from lithium titanate (LiTiO) pebble, we have carried out the DT neutron irradiation experiment at the Fusion Neutronics Source in Japan Atomic Energy Agency. Especially, we have investigated the influences of the temperature and the water moisture concentration in the sweep gas line on the ratio of the recovered tritium water and tritium gas (HT/HTO). The LiTiO pebbles (67g) put into a stainless steel container was inserted in an experimental assembly fabricated with beryllium and LiTiO blocks. DT neutron irradiation was performed, keeping the temperature of the pebbles uniformly, and recovered on-line the tritium generated within the pebble. The helium gas which contained dry hydrogen gas 1% was mainly used as the sweep gas. The moisture concentration in the helium gas was changed and the collected tritium recovery property for the moisture concentration was also investigated. The HTO and HT collected with water bubblers were measured by the liquid scintillation counter, respectively. From our tritium recovery online experiment, it was shown that the recovered tritium corresponded to the calculated tritium production within the experimental error in the range of 573-1073 K. It was also found that the ratio of the HTO and HT depended on the temperature and the tritium gas recovery was more than 95% at 1073 K.